# Hoowlib vs ShelfMark

The clearest difference is in-app purchases: Hoowlib at none against ShelfMark's 1. Hoowlib also leads on iOS requirement (15.0 vs 18.0). ShelfMark's advantage is update cadence (weekly vs every 2 months). On price, ads and device support there is nothing between them.

Both are free to download. ShelfMark sells 1 one-off in-app purchase. Hoowlib asks for nothing beyond the download.

Hoowlib ships an update every 2 months, ShelfMark weekly. The most recent releases landed on October 8, 2026 and October 3, 2026 respectively.

## The numbers

| Metric | Hoowlib | ShelfMark |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Weekly** |
| Size | 20 MB | 6 MB |
| Requires iOS | **15.0** | 18.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nikolas Palm](https://appshunter.io/developer/1825841930) | [InnovaLabWorks](https://appshunter.io/developer/1888514726) |

## What reviewers say

### Hoowlib

[App page](https://appshunter.io/ios/app/hoowlib/id6748452885)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### ShelfMark

[App page](https://appshunter.io/ios/app/shelfmark-reading-tracker/id6788129809)

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ShelfMark Lifetime | $12.99 | one-time |


## Frequently asked questions

### Is Hoowlib free?

Hoowlib is free to download, with no in-app purchases.

### Is ShelfMark free?

ShelfMark is free to download, with in-app purchases available.

### Do Hoowlib or ShelfMark have ads?

Neither Hoowlib nor ShelfMark shows ads.

### Which is updated more often, Hoowlib or ShelfMark?

Hoowlib ships an update every 2 months, and ShelfMark weekly. Most recently, Hoowlib was updated on October 8, 2026 and ShelfMark on October 3, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*